1. Technical Field
The present invention relates to a liquid jet head, a carriage unit, a pressure control method, and a liquid jet recording apparatus.
2. Background Art
Conventionally, as an apparatus for jetting liquid toward a recording medium, there is known a liquid jet recording apparatus for jetting a droplet from a plurality of nozzles toward a recording medium. Some liquid jet recording apparatus, for example, include a liquid jet head mounted thereon for jetting liquid as a droplet of several to several ten picoliters. A liquid jet head which jets such a minute droplet is adapted to control liquid in the nozzle so as to be optimum for being jetted in order to materialize satisfactory jetting of the liquid. Here, a state of liquid which is optimum for being jetted is a state in which the pressure of the liquid in the nozzle is a negative pressure and a meniscus is formed in the nozzle. In order to make such a pressure adjustment, there is known an apparatus in which a pump or an air valve is provided in a flow path of liquid between a liquid container and a liquid jet head for adjusting the pressure of liquid to be supplied to a nozzle.
Here, Patent Literature 1 (PTL) describes an ink jet printer (liquid jet recording apparatus) including a pump for depressurizing liquid in a nozzle of a liquid jet head, an air communication valve for pressurizing liquid in the nozzle of the liquid jet head, a pressure sensor for measuring the pressure of liquid in the nozzle of the liquid jet head, and a control portion for operating the pump and the air communication valve based on a measured value by the pressure sensor. In the ink jet printer, the pressure of liquid to be supplied to the nozzle is adapted to be increased or decreased by the pump and the air communication valve disposed in a liquid flow path from an auxiliary tank for storing liquid to the liquid jet head.